Method and apparatus for supplying coolant to grinding wheels



0 A J. 0. WILSON A 2,535,184

METHOD AND APPARATUS FOR SUPPLYING COOLANT T0 GRINDING WHEELS 2 Sheets-Sheet 1 Filed April 13, 1949 INVENTOR 70/! C. Wll50l BY 7 ATTORIEYS Dec. 26, 1950 2,535,184

- J. C. WILSON METHOD AND APPARATUS FOR SUPPLYING COOLANT '10 GRINDING WHEELS 2 Sheets-Sheet 2 Filed April 13, 1949 N N A Fa ilf-lii 8 llmvr A Toll/l C. W/L

Patented Dec. 26, 1950 METHOD AND APPARATUS FOR SUPPLYING COOLANT TO GRINDING WHEELS John C. Wilson, Springfield, Ohio, assignor to The Thompson Grinder Company, Springfield,

Ohio, a corporation of Ohio Application April 13, 1949, Serial No. 87,226

16 Claims.

This invention relates to grinding apparatus and particularly to methods and a paratus pertaining to the supplying of coolant to the grinding wheel.

In the art of grinding, one of the mo t important considerations is that of maintaining an adequate supply of the proper coolant to the point where the grinding wheel is engaged with the work piece. This is necessary in order to maintain the temperatures of the wheel and work piece within certain predetermined limits to prevent burning of the work piece and also to prevent deterioration of the grinding wheel.

It has been found that the quality of finish produced during grinding operations is materially enhanced by an adequate supply of coolant, and that the nearer the coolant is supplied directly to the area being operated on, the better the results. However, due to the fact that the grinding wheel is bearing directly on the work piece being operated, the conventional manner of supplying coolant to the wheel and work produces results far below the ideal.

Heretofore, the most usual practice has been to spray the coolant in the form of a jet from a pipe directed beneath the wheel toward the location where grinding is taking place. More recently, attempts have been made to supply coolant to the wheel from the inside thereof so that it throws out by centrifugal force and thus is projected radially into the zone where grinding is taking place.

It has been found that this latter manner of supplying coolant to a grinding wheel has particular benefits, and that greatly superior results are obtained if the coolant is properly supplied in this manner. All of the reasons why the grinding results are greatly superior are not known, but it is believed that a number of beneflcial factors come into play at this time.

For example, the supply of coolant is applied directly to the area being ground and is, therefore, highly effective for both lubricating and cooling. The supply of coolant can be made quite copious, and thisabsolutely insures that the temperature of the wheel and work piece at the grinding zone will be maintained within proper limits.

Also, due to the fact that grinding wheels opcrate at high speeds to obtain surface speeds of the order 6,000 feet per minute, there is considerable centrifugal force on coolant which is being supplied outwardly through the wheel, and the said coolant thus acts as an effective cleaning agent and maintains the pores of the wheel open and free of grit and other accumulations which ordinarily might build up therein during grinding or dressing.

In spite of the fact that definite advantages are obtained from supplying coolant to the grinding wheel from the inside out, no means has yet been devised for satisfactorily accomplishing this operation. 7

It has been attempted to supply coolant to a central cavity in the wheel and to coat the inner periphery of the central cavity or bore of the wheel with a substance somewhat less porous than the wheel, and in this manner to inhibit the outward flow of the coolant from the cavity to some extent, thereby permitting the fluid to distribute itself uniformly along the axial length and about the periphery of the cavity.

This arrangement for effecting distribution of the coolant has not been entirely successful because each grinding wheel is somewhat different from every other and each of the linings in the cavities must, therefore, be different. Each wheel, accordingly, must be tested and the cavity liner adjusted to meet the specific conditions which are obtained with that wheel. This procedure is troublesome to carry out, is not economical, and, accordingly, has not met with particular success or acceptance in the art.

The primary object of the present invention is to provide an improved method and arrangement for axially and circumferentially distributing coolant about the inner periphery of the center bore of a grinding wheel which overcomes the difflculties referred to above.

Another object of this invention is to provide a method and apparatus forsupplying coolant through a grinding wheel from the inside thereof outwardly, such that substantially'even distribution of the coolant is obtained at all times and with the use of a standard wheel.

A still further object is the provision of a. method and apparatus for supplying coolant from the inside of a grinding wheel outwardly such that the fluid flow in different parts of the wheel can be regulated to insure exactly uniform distribution.

These and other objects and advantages will become more apparent upon reference to the following description taken in connection with the accompanying drawings in which:

Figure 1 is a vertical section taken through a grinding wheel having a support constructed according to and adapted for practicing the method of my invention;

Figure 2 is a vertical section indicated by the line 22 on Figure 1;

F gure 3 is a view similar to Figure 1, but showing a somewhat modified arrangement wherein the grinding wheel is recessed on its opposite faces;

Figure 4 is a vertical section indicated by the,

line 44 on Figure 3;

Figure 5 is a view similar to Figures 1 and 3, but showing a grinding wheel having a single recess on one side thereof;

Figure 6 is a vertical section indicated by the line 8--6 on Figure 5;

Figure '1 isa view somewhat similar to Figure 6;

Figure 8 is a vertical section indicated byline 8-8 on Figure 7; and

Figure 9 is a fragmentary view showing how a grinding wheel, such as is illustrated in Figure 3, can have a part of its surface coated so as to direct the coolant out the face thereof.

Referring to the drawings somewhat more in detail, there is shown in Figures 1 and 2 a standard grinding wheel I 0 having a central bore l2 extending axially therethrough. The supporting shaft fonthe grinding wheel is indicated at l4, and it will be understood that this shaft is journaled and driven in the usual manner.

Mounted on the tapered end- 16 of the shaft and retained thereon by the clamping nut. is is a hub member 20 which extends through the bore I2 of the wheel.

The hub 2. has a rear flange 22 overlying the rear face ofthe wheel and a detachable front flange 24 overlying the front face of the wheel.

The body of the hub is of a smaller diameter than the diameter of the bore I! so as to leave an annular space between the outer periphery of the hub and the inner periphery of the bore II, as indicated in 26. v

The hub 20 is turned so as to have a pair of shoulders thereon as at 2-8, and fltting over the hub in abutment with the shoulders are the annular rin s 30. The rings 30 have a radial thickness exactly equal to the radial thickness of the chamber 26 in the planes of the rings, and the said rings, therefore, provide support for the wheel.

The rings, as will be best seen in Figure 2, comprise a plurality of circumferentially s aced axially extending notches 32 which provide for substantially free axial flow of fluid within the chamber 26.

'The rings 30 may also be peripherally grooved, as at 34, so as to provide for free circumferential flow of fluid about the chamber 26. It will be apparent that the rings 30, while providing radial support for the wheel l0, do not substantially inhibit fluid flow in the cavity 26 in any direction.

Neither is any substantial part of the area of the bore I! covered by the rings 30. The spaced points of engagement of the rings 30 with the bore I 2 provide adequate support for the wheel but leave substantially the entire surface of the bore open for receiving fluid.

The hub 20 has a central cavity or recess therein at 36 coaxial with the shaft l4. A cover plate 38 is mounted on the flange 24 to cover the cavity 36 and is centrally apertured. as at 40.

for receiving the-coolant supply conduit 42, and

which is also coaxial with the shaft l4.

Extending generally axially through the hub 2n and opening into the cavity 36 adjacent the outermost part thereof are a plurality of circumferentially spaced axial bores 44. It will be noted in Figure 1 that these bores are inclined outwardly from the cavity a substantial amount.

tending through the rings 30 open into the notches 32 of the rings so that all 01' the coolant supply is into the chamber 26 and none is delivered directly to the periphery of bore ii.

The peripheral grooves 34 in the rings 3|! are effective for preventing any nonuniformity of distribution of fluid about the chamber 26 clue to the nonuniform drilling of the bores 46.

In operation, the grinding wheel shown in Figures 1 and 2 is driven by the driving of the shaft l4 at the proper speed, and coo ant is supplied to the cavity 36 by the conduit 42. The coolant so supplied is thrown outwardly in the cavity 36 by the centrifugal force acting thereon as it assumes the rotational speed of the wheel, and then flows into the axial bores 44. The coolant, in flowing along the bores 44, enters the bores 46, and, because of the outward inclination of the bores 44, the distribution of fluid among the bores 46 is substantially uniform.

The fluid issues from the outer ends of the bores 46 into the chamber 26, and at this time is substantially' uniformly distributed over the entire periphery and axial length of the bore ii.

The amount of coolant supply through conduit 42 is preferably suflicient to maintain a continuous fllm of fluid about bore l2., The circumferential force, acting on this film bf fluid, throws it outwardly through the wheel, and it issues from the outer surface of the wheel as aflne and continuous spray.

As mentioned before, this spray is highly effective for cooling the wheel and also washing the pores thereof free of all accumulated foreign material so the grinding surface of the wheel is always maintained clean, sharp and cool.

It will be noted that due to the notches 32 and 34 in the rings 30, any slight nonuniformity of supply of fluid to the chamber 26 is automatically compensated for by the fluid seeking its own level.

The primary distribution of the fluid about the chamber 26, of course, takes place in the central cavity of the hub and in the passage means extending through the hub, and normally there is very little axial or circumferential flow in the fluid of the chamber 26. However, should such flow be necessary to obtain uniform distribution,

the notches 32 and 34 are adequate for that purpose.

The arrangement shown in Figures 3 and 4 is substantially identical with that shown in Figures 1 and 2, and corresponding parts of these views have been correspondingly numbered, but with the addition of a subscript a.

In Figure 3, itwill be noted that the wheel Ilia has a recess in the front face thereof, as at 48, and that the' front flange 24a is positioned within this recess, leaving the face of the wheel open. This is sometimes necessary to carry out particular grinding operations where there is not enough space -to permit the front flange to extend beyond the face of the wheel,

Figures 3 and 4 also illustrate another arrangement for insuring uniform distribution of the coolant fluid about and along the wheel. This is accomplished by placing in the outer end of each s v of the radial bores "a a nozzle or orifice member II. These members are preferably threaded into the ends of the bores so as to be readily removable to be replaced by other "members of a different orifice value.

In order to be able to use the entire length of the face of the wheel shown in Figure 3. the rear flange 220, has radial bores 52- therein corresponding to the bores 48a.

The bores 52 open into an annular chamber '4 extending around the outside of the flange 22a and are provided with nozzle or oriilce members Bl corresponding to the members I.

The front flange 24a is similarly radially bored, as at ill, and these bores are also provided with orifice members it which open into chamber-l2.

In connection with the bores 52 and 58 in the flanges 22a and a, it is to be noted that the coolant has less radial distance to travel outwardly through the wheel after it leaves the ends of these bores. This is an additional reason for providing the oriflce members 56 and 80 in these bores which operate to prevent an oversupply of coolant through the front and back parts of the vmeel.

Figures nd 6 show a wheel arrangement substantially identical with that shown in Figures 1 and 2. and corresponding parts are correspondingly numbered with the addition of a subscript b." In Figure 5 it will be noted that the wheel has a single recess 84 in its rear face for receiving the flange 22b, and that this flange is radialy bored as at 6C similarly to flange 22a in Figure 3.

In Figures 5 and 6 the hub 20b is banded with a plurality of annular bands 68 and has holes registering with the radial bores 46b. These bands are angularly adjustable about the hub 20!) to vary the efl'ective areas of the bores 48b and thus to vary the coolant flow through any co-planar set thereof relative to the others.

The two of the ,bands beneath the rings 30b 1 have pins I0 extending through the rings so the bands can be adjusted, but all of the other bands I! are readily accessible for adjustment without the need of similar pins thereon. Suitable means could be provided, if desired, for clamping the rings in place.

Figures 7 and 8 show still another modification of my invention, and parts of these views correspond with'those of Figures 1 and 2 and are correspondingly numbered with the addition of a subscript c.

The wheel lllc in Figures '7 and 8 has a single recess 12 for receiving the flange 22c, and which flange is radially bored, as at 16.

The hub is bored substantially identically with the hub shown in Figure 5, except that the outer ends of the bores have the adjustable nozzle or orifice members 1| therein corresponding to the members in Figure 3. v

In Figure 7 it will be noted that the radial bores in the flange 220 are somewhat smaller than the bores to, as is also the case in connection with bores 66 and bores 46b in Figure 5. I

This provision of smaller bores in the flanges, together with the use of nozzle members in the outer ends of the bores having restricted orifices therein counteracts the tendency for the coolant flow through this part of the wheel to be greater than through the other parts thereof.

Figure 9 is a fragmentary view showing how the outer and rear face of a grinding wheel, such as is shown in Figure 3, can be sealed as by a coating 18 so that the coolant is forced through the front face 80 of the wheel.

assures This arrangement is .useful when the wheel is used entirely for face grinding.

It will be seen that what this invention provides is a new and useful method and apparatus for insuring absolutely uniform distribution of coolant about the circumference and along the length of -a grinding wheel by introducing the coolant into a central cavity in" the supporting hub for the wheel, conveying the fluid from the central cavity and distributing it uniformly about a chamber surrounding the hub and whose outer surface is the inner surface of the central bore of the grinding wheel.

It is not necessary, when using the present invention, to coat the central bore of the wheel or otherwise to modify the wheel in any way whatsoever because the important step of uniformly distributing the fluid before it is supplied to chamber It obviates the need for any special treatment of the wheel proper.

It will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions, and, accordingly, it is desired to comprehend such modiflcations within this invention as may fall within the scope of the appended claims.

I claim:

1. In combination with a grinding wheel having a central axial cavity, a hub in said cavity of smaller diameter than the cavity to form.

therewith an annular chamber. flange means on said hubiengaging opposite faces of the wheel and supporting the wheel on the hub, said hub having a central recess, said hub having a plurality of circumferentially spaced substantially axial passage means extending from said recess partway through said hub, and said hub also having a plurality of substantially radial passage means connecting each said axial passage means with said chamber.

2. In combination with a grinding wheel having a central axial cavity, a hub in said cavity of smaller diameter than the cavity to form therewith an annular chamber, flange means on said hub engaging opposite faces of the wheel and supporting the wheel on the hub, there being a central recess in one face of said hub, said hub having a plurality of circumferentially spaced substantially axial passage means extending from said recess partway through said hub and said hub also having a plurality of substantially radial passage means connecting each axial passage means with said chamber, said axial passage means beingoutwardly inclined from their open ends toward their closed ends.

3. In combination in a grinding wheel having a central axial bore therethrough, a hub in said bore being of smaller diameter than the bore to form therewith an annular chamber, annular rings fitting over said hub and in said bore, flange means on said hub engaging opposite faces of said wheel, there being a central recess in one face of said hub, said hub having a plurality of circumferentially spaced axially and outwardly extending bores opening into said recess at their inner ends, said hub'also having a plurality of substantially radial bores opening from said axial bores into said chamber, and means for supplying coolant to said recess whereby it is distributed by the bores in said hub about the entire periphery and axial length of said chamber. I

4. In combination in a grinding wheel having a central axial bore therethrough, a hub in said bore being of smaller. diameter than the bore to form therewith an annular chamber, annular rings fitting over said hub and in said bore, flange means on said hub engaging opposite faces of said wheel, there being a central recess in one face of said hub, said hub having a plurality of circumferentially spaced axially and outwardly extending bores opening into said recess at their inner ends, said hub also having a plurality of substantially radial bores opening from said axial bores into said chamber, and means for supplying coolant to said .recess whereby it is distributed by the bores in said hub about the entire periphery and axial length of said chamber, said annular rings being transversely slotted about their outer peripheries so as to maintain continuous communication between opposite ends of said bore.

5. In combination in a grinding wheel having a central axial bore therethrough, a hub in said bore being of smaller diameter than the bore to form therewith .an annular chamber, annular rings fitting over said hub and in said bore, flange means on said hub engaging opposite faces of said wheel, there being a central recess in one face of said hub, said hub having a pluralit of circumferentially spaced axially and outwardly extending bores opening into said recess at their inner ends, said hub also having a plurality of substantially radial bores opening from said axial bores into said chamber, and means for supplying coolant to said recess whereby it is distributed by the bores in said hub about the entire periphery and axial length of said chamber, the said annular rings being circumferentially and transversely slotted about their outer peripheries for maintaining the continuity of said chamber and so as not to inhibit fluid flow therein.

6. In combination with a grinding wheel having a central bore, a hub in said bore smaller in diameter than the bore to form an annular chamber therewith, flange means on said hub engaging opposite faces of said wheel and forming end closures for said chamber, spaced annular rings fltting over said hub and within said bore for providing radial support for said wheel, said hub having a central recess, and a plurality of circumferentially spaced passage means extendin in substantially axial planes from said recess part way through said hub and inclined outwardly toward, their closed ends, said hub also having a plurality of radial passage means opening from each of said axial passage means into said chamber, and means for selectively adjusting the effective areas of said radial passage means to regulate the distribution of coolant about said chamber.

7.In combination with a grinding wheel having a central bore, a hub in said bore smaller in'diameter than the bore to form an annuar chamber therewith, flange means on said hub engaging opposite faces of said wheel and forming end closures for said chamber, spaced annular rings fitting over said hub and within said bore for providing radial support for said wheel, said hub having a central recess, and circumferentially spaced passage means extending in substantially axial planes from said recess part way through said hub and inclined outwardly toward their closed ends, said hub also having a plurality of radial passage means distributed along the length of and opening from each of said axial passage means into said chamber, and means for selectively adjusting the effective areas of said radial passage means to regulate the distribution of coolant about said chamber, said means comprising nozzle means detachabl mounted in said radial passage means.

8. In combination with a grinding wheel having a central bore, a hub in said bore smaller in diameter than the bore to form an annular chamber therewith, flange means on said hub engaging opposite faces of said wheel and forming end closures for said chamber, spaced annular rings fitting over said hub and within said bore for providing radial support for said wheel, said hub having a central recess, and circumferentially spaced passage means extending in substantially axial planes from said recess part way through said hub and inclined outwardly toward their closed ends, said hub also having a plurality of radial passage means distributed along and opening from each of said axial passage means into said chamber, and means for selectively adjusting the effective areas of said radial passage means to regulate the distribution of coolant about said chamber, said means comprising annular bands mounted about said hub having apertures adapted for registration with said radial passage means and adjustable for varying the degree of said registration.

9. In combination with a grinding wheel having a central bore, a supporting hub in said bore smaller in diameter than the bore so as to form therewith an annular chamber, flanges on said hub engaging opposite faces of said wheel and forming end closures for said chamber, axially spaced annular rings fitting over said hub and within said bore to provide radial support for said wheel, said hub having a central recess and means for supplying coolant thereto, said hub also having a plurality of axially and outwardly extending passage means extending from adjacent the outer periphery of said recess toward but not to the other side of the hub, said hub also having substantially radially extending passage means distributed along and opening from said axial passage means into saidchamber, said rings including radial passage means forming continuations of some of said radial passage means in said hub, and transvers and circumferential notches in .theouter peripheries of said rings to maintain the continuity of said chamber about at least its outer periphery.

10. In combination with a grinding wheel having a central bore, a supporting hub in said bore smaller in diameter than the bore so as to form therewith an annular chamber, flanges on said hub engaging opposite faces of said wheel and forming end closures for said chamber, axially spaced annular rings fitting over said hub and within saidbore to provide radial support for said wheel, said hub having a central recess and means for supplying coolant thereto, said hub also having a plurality of axially and outwardly extending passage means extending from adjacent the outer periphery of said recess toward but not to the other side of the hub, said hub also having substantially radially extending passage means opening from said axial passage means into said chamber, radial passage means in said rings forming continuation of some of said radial passage means in said hub, transverse and circumferential notches in the outer peripheries of said rings to maintain the continuity of said chamber about at least its outer periphery, and means for adjusting the effective areas of said radial passage means to control the distribution of coolant about said chamber to obtain a uniform supply thereof at the working face of said wheel.

11. In combination with a grinding wheel having a central bore, a supporting hub in said bore smaller in diameter than the bore so as to form therewith an annular chamber, flanges on said hub engaging opposite faces of said wheel and forming end closures for said chamber, axially spaced annular rings fitting over said hub and within said bore to provide radial support for said wheel, said hub having a central recess and means for supplying coolant thereto, said hub also having a plurality of axially and outwardly extending passage means extending from adjacent the outer periphery of said recess toward but not to the other side of the hub, said hub also having substantially radially extending passage means opening from said axial passage means into said chamber, said rings having radial passage means forming continuations f some of said radial passage means in said hub, transverse and circumferential notches in the outer peripheries of said rings to maintain the continuity of said chamber about at least its outer periphery, and nozzle A supply of coolant to the working face of the wheel.

12. In combination with a grinding wheel having a recess in at least one face thereof and a central axialbore, a hub in said bore smaller in diameter than the bore so as to form an annular chamber therewith, a first flange on said hub in said recess and another flange on said hub engaging the opposite face of said wheel, annular rings fitting over said hub and in said bore to provide radial support for said wheel, there being a central recess in one face of said hub, said hub also having passage means connecting said central recess in said hub with said chamber, said first flange having radial bores forming continuations of some of said passage means and opening radially outwardly through the said flange, said passage means and bores serving to convey c001- ant from said central recess to said chamber and about the periphery of the recess receiving said first flange, said passage means being distributed about said hub and flange so as to produce substantially uniform coolant supply at the working face of said wheel.

13. In combination with a grinding wheel having recesses in its opposite faces and an axial bore, a hub in said bore forming therewith an annular chamber and flanges on said hub in said recesses, said hub having a central recess and said hub and flanges having passage means connecting said central recess with said chamber and with the peripheries of the recesses in said wheel, said passage means being distributed about said hub and flanges so as to produce a substantially uniform supply of coolant to the working face of said wheel.

14. In combination with a grinding wheel having recesses in its opposite faces and an axial bore, a hub in said bore forming therewith an annular chamber and flanges on said hub in said recesses, said hub having a central recess, and said hub and flanges having passage means connecting said central recess with said chamber and with the peripheries of the recesses in said wheel, said passage an annular chamber therewith, flange means on said hub engaging opposite faces of said wheel for supporting the wheel on said hub and closi the ends of said chamber, said hub having a central recess in its outer end, there being a plurality of passage means in said hub connecting said central recess with said chamber, said passage means extending axially and radially through the hub and having their inner ends distributed about the periphery of the recess and their outer ends distributed about the circumference and length of the outer surface of the hub to provide for substantially uniform circumferential and axial distribution of fluid to said chamber.

16. In the art of grinding, the method of supplying coolant to a relatively wide grinding wheel having a central cavity and a supporting hub therein which comprises; supplying coolant axially to the center of the hub, conveying the coolant radially and axially through the hub and discharging it radially from the outer periphery thereof about the entire periphery and the entire axial length of the cavity, and distributing the coolant during its passage through said hub uniformly over the length and circumference of the hub to obtain substantially uniform distribution of the coolant in said cavity.

JOHN C. WILSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Num er Name Date Re. 16,043 Joseph -e Apr. 14, 1925 164,692 Putnam et al June 22, 1875 376,854 Cavert Jan. 24, 1888 455,277 Cummins June 30, 1891 500,561 Carpenter et al July 4, 1893 524,572 Beckert Aug. 14, 1894 796,466 Stolzenberg Aug. 8, 1905 1,404,538 Mitchell Jan. 24, 1922 2,089,040 Shue Aug. 3, 1937 2,167,282 Murphy July 25, 1939 2,380,332 Scheer July 10, 1945 2,470,350 Harrington May 17, 1949 FOREIGN PATENTS Number Country Date 34,151 Germany Sept. 11, 1884 500,485 Germany Jan. 23, 1929 511,547 Germany June 30, 1929 

